The present invention relates to a wireless connection system, and more specifically to a method for efficiently transmitting a control channel in a multi-carrier aggregation state. According to one aspect of the invention, a method for enabling a terminal to transmit data in a broadband wireless connection system that supports multiband comprises the steps of: receiving uplink acknowledgement information from a base station through a first downlink component carrier among plural downlink component carriers available in the terminal; transmitting data to the base station through an uplink resource indicated by the uplink acknowledge information; and receiving feedback information from the base station through the first control channel of the first downlink component carrier, wherein the feedback information indicates whether there is an error in the reception of the transmitted data.